Comprehending a list comprehension!

[alidaf]

I have been given some example code that captures BLE broadcasts from beacons but there's a line that is really confusing me:

data = [b for b in device.data]

device.data is a list that contains BLE broadcast data from the bluetooth.get_adv() MicroPython function. It can hold up to 16 devices.

I just don't understand the syntax. b is not used anywhere and I don't get what b for b is actually doing, especially since it isn't defined anywhere.

I think this is a 'list comprehension' but the explanations I have found are addling my noodle. How would this expand into a normal, sane 'for loop'?